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VarAction2: Add helper functions for anti-commutative ops

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This commit is contained in:
Jonathan G Rennison
2022-06-08 19:15:56 +01:00
parent 5db30e559e
commit 31e96ff5e7
2 changed files with 35 additions and 11 deletions
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14
src/newgrf.cpp
View File

@@ -6941,20 +6941,12 @@ static std::bitset<256> HandleVarAction2DeadStoreElimination(DeterministicSprite
const DeterministicSpriteGroupAdjust &next2 = group->adjusts[i + 2];
if (next2.type == DSGA_TYPE_NONE && next2.variable == 0x7D && next2.shift_num == 0 &&
next2.and_mask == 0xFFFFFFFF && next2.parameter == prev.and_mask) {
bool found = false;
if (IsEvalAdjustOperationCommutative(next2.operation)) {
/* Convert: store, load var, commutative op on stored --> (dead) store, commutative op var */
next.operation = next2.operation;
if (IsEvalAdjustOperationReversable(next2.operation)) {
/* Convert: store, load var, (anti-)commutative op on stored --> (dead) store, (reversed) (anti-)commutative op var */
next.operation = ReverseEvalAdjustOperation(next2.operation);
if (IsEvalAdjustWithZeroLastValueAlwaysZero(next.operation)) {
next.adjust_flags |= DSGAF_SKIP_ON_ZERO;
}
found = true;
} else if (next2.operation == DSGA_OP_SUB || next2.operation == DSGA_OP_RSUB) {
/* Convert: store, load var, sub/rsub op on stored --> (dead) store, rsub/sub op var */
next.operation = (next2.operation == DSGA_OP_SUB) ? DSGA_OP_RSUB : DSGA_OP_SUB;
found = true;
}
if (found) {
erase_adjust(i + 2);
restart();
break;

32
src/newgrf_spritegroup.h
View File

@@ -300,6 +300,38 @@ inline bool IsEvalAdjustOperationCommutative(DeterministicSpriteGroupAdjustOpera
}
}
inline bool IsEvalAdjustOperationAntiCommutative(DeterministicSpriteGroupAdjustOperation op)
{
switch (op) {
case DSGA_OP_SUB:
case DSGA_OP_RSUB:
return true;
default:
return false;
}
}
inline bool IsEvalAdjustOperationReversable(DeterministicSpriteGroupAdjustOperation op)
{
return IsEvalAdjustOperationCommutative(op) || IsEvalAdjustOperationAntiCommutative(op);
}
inline DeterministicSpriteGroupAdjustOperation ReverseEvalAdjustOperation(DeterministicSpriteGroupAdjustOperation op)
{
if (IsEvalAdjustOperationCommutative(op)) return op;
switch (op) {
case DSGA_OP_SUB:
return DSGA_OP_RSUB;
case DSGA_OP_RSUB:
return DSGA_OP_SUB;
default:
NOT_REACHED();
}
}
inline bool IsEvalAdjustOperationOnConstantEffectiveLoad(DeterministicSpriteGroupAdjustOperation op, uint32 constant)
{
switch (op) {